If I remember correctly, this isn't a souvenir but is a badge, and after we qualified we got a message (or email?) or saw on a blog what we had to do to get the icon. The details are now a bit vague. It's the kind of thing that I don't see any reason to remember, so I'm now fuzzy on the details.
I recall some folks periodically complaining that they didn't get souvenirs added to their profile after completing whatever task was required to earn it. In most cases, they simply contacted GC and somebody took care of it cheerfully after verifying logs, dates, etc.
For my part, I've only had one issue a couple years ago, but it seemed to be related to the way I logged the caches that somehow mucked things up. Basically, my logged date fell outside the qualifying zone required for the award. Once I corrected the find date/time all was good and the award showed up in my profile.
I've never done anything deliberately before to get a souvenir, but I have a handful. In looking at peoples profiles I noticed this icon for "Haunted Hides."
I had to google it but it seems you get a souvenir if you found a cache on certain days last year. Turns out I did, but I have no haunted hides souvenir. So, what's the deal?